CVE-2021-23758
HIGH severity · CVSS 8.1 · Insecure deserialization · actively exploited (CISA KEV)
8.1CVSS HIGH exploited
Actively exploited in the wild (CISA Known Exploited Vulnerabilities).
Added to KEV 2026-08-26. US federal agencies must patch by 2026-09-09.
Summary
All versions of package ajaxpro.2 are vulnerable to Deserialization of Untrusted Data due to the possibility of deserialization of arbitrary .NET classes, which can be abused to gain remote code execution.
Impact & exploitability
Attack vectorNetwork
Attack complexityHigh
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)89%
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products we track (1)
Recommendation
This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.
Official patch: https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57 ↗
Additional information
- NVD record
- https://github.com/michaelschwarz/Ajax.NET-Professional/commit/b0e63be5f0bb20dfce507cb8a1a9568f6e73de57Patch
- https://snyk.io/vuln/SNYK-DOTNET-AJAXPRO2-1925971Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-23758
- http://packetstormsecurity.com/files/175677/AjaxPro-Deserialization-Remote-Code-Execution.htmlExploit
- https://blog.talosintelligence.com/uat-10147-chinese-speaking-adversary-integrates-agentic-ai-into-post-compromise-operations/Advisory